Twitter takes step to make it harder to spy on its users

－－Twitter采取更强措施保护用户信息

TwitterIncsaid it has implemented a securitytechnology that makes it harder to spyonitsusersandcalledonotherInternetfirms to do the same, asWebproviderslook to thwartspying by governmentintelligenceagencies.

The onlinemessagingservice, which beganscramblingcommunications in 2011 usingtraditional HTTPS encryption, said on Friday it has added an advancedlayer of protection for HTTPS knownas "forwardsecrecy."

"A year and a half ago, Twitter was firstservedcompletelyover HTTPS," the companysaid in a blogposting. "Sincethen, it has becomeclearerandclearer how importantthatstep was to protecting our users' privacy."

Twitter's move is the latestresponse from U.S.Internetfirmsfollowingdisclosures by formerspyagencycontractor Edward Snowden aboutwidespread, classifiedU.S.governmentsurveillanceprograms.FacebookInc, GoogleInc, MicrosoftCorpandYahooInc have publiclycomplained that the government does not let them disclosedatacollectionefforts.Some have adoptednewprivacytechnologies to bettersecureuserdata.

Forwardsecrecypreventsattackersfromexploitingonepotentialweakness in HTTPS, which is that largequantities of data can be unscrambledifspies are able to steal a singleprivate "key" that isthenused to encryptall the data, said Dan Kaminsky, a well-knownInternetsecurityexpert.

The moreadvancedtechniquerepeatedlycreatesindividualkeysasnewcommunicationssessions are opened, making it impossible to use a masterkey to decrypt them, Kaminsky said.

"It is a goodthing to do," he said. "I'm gladthis is the direction the industry is taking."